/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

@group(0) @binding(0) var<storage, read> input: array<f32>;
@group(0) @binding(1) var<storage, read> flags: array<u32>;
@group(0) @binding(2) var<storage, read> prefix: array<u32>;
@group(0) @binding(3) var<storage, read_write> output: array<f32>;

@compute @workgroup_size(256)
fn main(@builtin(global_invocation_id) gid: vec3<u32>) {
    let i = gid.x;
    let n = arrayLength(&flags);
    if (i >= n) { return; }
    if (flags[i] != 0u) {
        let dst = prefix[i];
        output[dst] = input[i];
    }
}